Many-qubit quantum state transfer via spin chains

TL;DR

This paper extends quantum state transfer protocols to enable the transfer of two qubits using spin chains, employing Rabi-like oscillations and deriving exact fidelity formulas for high-quality transfer.

Contribution

It introduces a modified protocol for two-qubit transfer via spin chains, addressing a gap in multi-qubit quantum communication methods.

Findings

Achieves high-fidelity two-qubit transfer using magnetic field-induced excitations.

Provides exact analytical formulas for transfer fidelity.

Demonstrates effectiveness for general and specific quantum states.

Abstract

The transfer of an unknown quantum state, from a sender to a receiver, is one of the main requirements to perform quantum information processing tasks. In this respect, the state transfer of a single qubit by means of spin chains has been widely discussed, and many protocols aiming at performing this task have been proposed. Nevertheless, the state transfer of more than one qubit has not been properly addressed so far. In this paper, we present a modified version of a recently proposed quantum state transfer protocol [Phys. Rev. A 87, 062309 (2013)] to obtain a quantum channel for the transfer of two qubits. This goal is achieved by exploiting Rabi-like oscillations due to excitations induced by means of strong and localized magnetic fields. We derive exact analytical formulae for the fidelity of the quantum state transfer, and obtain a high-quality transfer for general quantum states as well as for specific classes of states relevant for quantum information processing.